Exemplary embodiments of the present invention are directed to a restraint device for a motor vehicle.
German Patent Documents DE 10 2007 052 246 A1 and DE 10 2007 022 925 A1 disclose restraint devices in the form of airbags that comprise a support structure moveable from a stowage position into a restraint position. This support structure is formed from a plurality of flexible tubular elements which, when triggered in an accident, are filled with a medium and thereby unfolded or increased in volume. A covering, which is arranged outside or inside the supporting structure or which fills individual partitions between the individual tubular elements of the support structure, is unfolded together with the support structure as the latter is transferred from the stowage position into the restraint position and surrounds a restraint volume. In order to ensure that the covering can unfold quickly and that a partial vacuum is not generated within the restraint volume, at least one ventilation opening is provided within the covering, via which opening a medium, in particular ambient air, can enter the covering during the movement into the restraint position. As soon as the restraint device is in its restraint position, a person hitting the device is essentially accommodated by the corresponding displacement of the medium, in particular the ambient air, within the restraint volume.
In order to protect a person in an accident as well as possible by means of the restraint device, it is advantageous if the person is already supported after covering a relatively short distance.
The present invention is therefore directed to a restraint device in which the support structure allows the person to be caught very efficiently.
A restraint device according to the invention, in particular for a motor vehicle and especially for a car, which comprises a support structure with a plurality of structural elements, which support structure can be moved from a stowage position into a restraint position, and which further comprises a covering by means of which a restraint volume formed by the support structure in its restraint position is surrounded, includes at least one support element by means of which at least one of the structural elements of the support structure is held in a predetermined form and/or position at least in the restraint position. As a result, the support structure can, in an accident, catch and support a person hitting the support structure in an interior of the motor vehicle particularly efficiently, because the person has to plunge into the support structure or the structural elements only very slightly before the support structure offers a sufficiently strong resistance to restrain the person.
In this process, a sufficiently high internal pressure for supporting the person builds up in the restraint volume after a very short plunging distance into the support structure or the structural elements. This is due to the fact that the at least one structural element is held in the predetermined form and/or position by the support element and is thereby preloaded and reinforced in the predetermined form and/or position, which facilitates the restraining function of the restraint device. In other words, the structural element or the surfaces of the structural element that are impacted by the person in the accident is/are already preloaded towards the restraint position before the person impacts the support structure or the structural element, whereby the internal pressure in the restraint volume is increased. The surfaces of the structural element are, for example, curved inwards, i.e., into the restraint volume. Without the support element, the surfaces could be curved outwards, i.e., away from the restraint volume into the passenger compartment of the motor vehicle, so that the surfaces first have to be curved inwards before a sufficiently high internal pressure for restraining, catching or supporting the person is built up in the restraint volume.
As the surfaces are already curved inwards by the support element before the person hits the support structure, the internal pressure is high enough to restrain the person after a short time, i.e., after a short plunging distance. The restraint device according to the invention therefore offers a very good restraining function, which allows the person to be caught after a very short distance. This avoids or at least reduces the probability of injuries in an accident.
In an advantageous embodiment of the invention, the support element is designed as a strap element, in particular as a retaining strap, by means of which the structural element is preloaded and thereby held in an advantageous predetermined form and/or position. By means of the retaining strap, the shape and in particular an external contour of the structural element can be adjusted such that the internal pressure is high enough to support the person in an accident after a very short plunging distance.
Alternatively, the support element can be designed as a seam by means of which darts are formed in parts of the volume element. Such darts can likewise hold and preload the support element in the predetermined position and in particular in the predetermined form, resulting in a very good restraining function of the restraint device.
If designed as a strap element or a seam in particular, the support element makes it possible to divide at least parts of an internal volume of the structural element which has to be filled with a medium, in particular gas, i.e., inflated, in order to move the support structure into the restraint position, into smaller individual volumes, wherein such an individual volume may, for example, act together with a gas generator. The gas generator fills the internal volume of the support element with gas in order to increase the volume. Initially, the gas generator blows the gas into the smaller individual volume, which therefore acts as a gas generator chamber with a smaller volume. Due to its small volume, this individual volume acting as gas generator chamber can be filled with gas and therefore inflated particularly fast, resulting in a particularly fast movement of the support structure into the restraint position. This benefits the restraining function of the restraint device, because the person can be caught by the support structure within a particularly short time in an accident after a motor vehicle hits a barrier.
In this way, the support element allows a simple connection of the gas generator to at least almost any position of the restraint device, the gas generator being in particular held on a housing of the restraint device. At least parts of the support structure are accommodated in this housing in the stowage position. The gas generator, for example, fills the structural element or the individual volume with gas via at least one through-opening in a wall, in particular in a base, a side wall or an edge, of the housing. Alternatively, the gas generator can be mounted in any other position, thereby supplying gas to a structural element which—at least in the restraint position—is not in close proximity to the housing. In other words: the support element allows the airbag to be filled efficiently and effectively, in particular due to an expedient shaping of the structural element, the form and/or position of which can be adjusted for efficient and effective gas filling by the support element.
The support element further reduces resistances, in particular flow resistances, of the restraint device, so that the support structure can be moved into the restraint position particularly fast. This is accompanied by good gas distribution and distribution of forces as the support structure moves into the restraint position. As a result, the support structure can have a minimum wall thickness and/or be made of a particularly light-weight material. The support structure therefore has a very low weight, which further facilitates a fast movement into the restraint position with a further beneficial effect on the restraining function of the restraint device.
The support element can be sewn and/or bonded to the structural element and/or be designed as an insert part that is installed into the internal volume of the structural element. The support element is therefore joined to the structural element in a cost-effective way. The bonding and/or sewing process further allows a seam to be adjusted to requirements particularly easily, so that the structural element can be held in a particularly advantageous position and/or form that may have a complex geometry.
In a particularly advantageous embodiment of the invention, the support element is substantially designed as a tubular, inherently rigid support element. In this way, it is designed analogous to a so-called stent. Such a stent as known from human medicine is a support for blood vessels, which in human medicine is installed into hollow organs and in the restraint device according to the invention into the internal volume of the structural element in order to keep the hollow organ or the structural element respectively open. This may, for example, be a small tubular lattice made of metal or a plastic material. The support element therefore prevents an undesirable folding or kinking of the structural element—advantageously already in the stowage position of the support structure, so that the structural element and the support structure can be filled with gas and the filling of the structural element and the support structure is not impeded by such a fold or kinking.
Due to the fact that the support element facilitates a particularly effective and efficient movement of the support structure into the restraint position, for example as a result of the filling of the structural element(s) or the support structure with gas, and that a folding or kinking is avoided, the structural element or the support structure respectively can be produced as a cheap so-called two-dimensional (2D) structure that requires very little space in the stowage position. Thus, the structural element can be formed, for example, from only two fabric mats that extend substantially parallel to each other and which are, for example, sewn flat together in edge regions, so that the internal volume of the structural element can be filled with the gas between the seams. Further fabric elements, in particular fabric mats that extend at an angle, in particular at right angles, to the above fabric mats are therefore not provided.
These additional fabric elements are, for example, used to form a so-called three-dimensional (3D) structure, so that the structural element even in the stowage position has a shape that is identical or at least similar to its shape in the restraint position, in which the internal volume is filled with the medium, in particular gas. A 3D structure of the structural element formed in this way likewise prevents folding or kinking and therefore facilitates an effective and efficient movement of the support structure into the restraint position while at the same time meaning that the structural element and thus the entire support structure requires much space, particular in the stowage position, and is moreover heavy.
The support element makes it possible to design the structural element and the support structure as a whole as a very light-weight 2D structure that requires very little space while providing for a very effective and efficient movement into the restraint position because folds and kinking are avoided.
Further advantages, features and details of the invention can be derived from the following description of preferred embodiments and from the drawing. The features and feature combinations mentioned in the above description and the features and feature combinations mentioned below in the description of the figures and/or shown in the figures only can be used not only in the specified combination but also in other combinations or individually without leaving the scope of the invention.